1. Field of the Invention
The present invention relates to an image processing apparatus, an image processing method and an image processing program to detect, from an image, a region onto which a bubble has been imaged.
2. Description of the Related Art
Conventionally, endoscopes are widely used as medical observation devices, which are introduced into the body of examinees such as patients and through which the insides of living organisms are non-invasively observed. In recent years, even an endoscope (capsule endoscope) to be swallowed has been developed, which has a capsule-shaped casing to accommodate an imaging device, a communication device and the like, and wirelessly transmits image data captured by the imaging device to the outside of the body. The number of images (in-vivo images) obtained in series by imaging the interior of a lumen by use of such a medical observation device is enormous (not less than tens of thousands), and observing and diagnosing each in-vivo image requires abundant experience. Therefore, a medical diagnosis support capability to assist a doctor in diagnosis is desirable.
As one image recognition technology that implements such a capability, a technology for automatically detecting and removing from images any regions not requiring to be observed in a medical diagnosis has been proposed. Here, the regions not requiring to be observed are regions other than a mucous membrane, which is a biological tissue, and include, for example, a region (hereinafter, referred to as “bubble region”) onto which an air bubble (hereinafter, referred to simply as “bubble”) generated in the interior of a lumen has been imaged. For example, Japanese Laid-open Patent Publication No. 2007-313119 discloses a method for calculating correlation values between gradient magnitudes of pixels and bubble models having been preset on the basis of features of bubble images, and detecting as a bubble region a region that gives the correlation value of a predetermined threshold or more.